Endometrial Cancer Prevention (PDQ®)
What is prevention?
Cancer prevention is action taken to lower the chance of getting cancer. By preventing cancer, the number of new cases of cancer in a group or population is lowered. Hopefully, this will lower the number of deaths caused by cancer.
To prevent new cancers from starting, scientists look at risk factors and protective factors. Anything that increases your chance of developing cancer is called a cancer risk factor; anything that decreases your chance of developing cancer is called a cancer protective factor.
Some risk factors for cancer can be avoided, but many cannot. For example, both smoking and inheriting certain genes are risk factors for some types of cancer, but only smoking can be avoided. Regular exercise and a healthy diet may be protective factors for some types of cancer. Avoiding risk factors and increasing protective factors may lower your risk but it does not mean that you will not get cancer.
Different ways to prevent cancer are being studied, including:
- Changing lifestyle or eating habits.
- Avoiding things known to cause cancer.
- Taking medicines to treat a precancerous condition or to keep cancer from starting.
General Information About Endometrial Cancer
Endometrial cancer is a disease in which malignant (cancer) cells form in the tissues of the endometrium.Anatomy of the female reproductive system. The organs in the female reproductive system include the uterus, ovaries, fallopian tubes, cervix, and vagina. The uterus has a muscular outer layer called the myometrium and an inner lining called the endometrium.
See the following PDQ summaries for more information about endometrial cancer:
Endometrial cancer is the most common invasive cancer of the female reproductive system.
Since 1992, the number of white women diagnosed with endometrial cancer has remained stable, but the number of new cases in black women has increased slightly. Endometrial cancer occurs more often in white women than in black women. When endometrial cancer is diagnosed in black women, it is usually more advanced and less likely to be cured. The number of deaths from endometrial cancer has stayed about the same in white women but has increased slightly in black women each year since 1998.
Endometrial Cancer Prevention
Avoiding risk factors and increasing protective factors may help prevent cancer.
Avoiding cancer risk factors may help prevent certain cancers. Risk factors include smoking, being overweight, and not getting enough exercise. Increasing protective factors such as quitting smoking, eating a healthy diet, and exercising may also help prevent some cancers. Talk to your doctor or other health care professional about how you might lower your risk of cancer.
The following risk factors may increase the risk of endometrial cancer:
Estrogen is a hormone made by the body. It helps the body develop and maintain female sex characteristics. Estrogen can affect the growth of some cancers, including endometrial cancer. A woman's risk of developing endometrial cancer is increased by being exposed to estrogen in the following ways:
- Estrogen-only hormone replacement therapy: Estrogen may be given to replace the estrogen no longer produced by the ovaries in postmenopausal women or women whose ovaries have been removed. This is called hormone replacement therapy (HRT), or hormone therapy (HT). The use of hormone replacement
therapy that contains only estrogen increases the risk
of endometrial cancer. For this reason, estrogen therapy alone is usually prescribed only for women who do not have a uterus.
When estrogen is combined with progestin (another hormone), it is called combination estrogen-progestin replacement therapy. For postmenopausal women, taking estrogen in combination with progestin does not increase the risk of endometrial cancer, but it does increase the risk of breast cancer, heart disease, stroke, and blood clots.
- Early menstruation: Beginning to have menstrual periods at an early age increases the number of years the body is exposed to estrogen and increases a woman's risk of endometrial cancer.
- Late menopause: Women who reach menopause at an older age are exposed to estrogen for a longer time and have an increased risk of endometrial cancer.
- Never being pregnant: Because estrogen levels are lower during pregnancy, women who have never been pregnant are exposed to estrogen for a longer time than women who have been pregnant. This increases the risk of endometrial cancer.
Tamoxifen is one of a group of drugs called selective estrogen receptor modulators, or SERMs. Tamoxifen acts like estrogen on some tissues in the body, such as the uterus, but blocks the effects of estrogen on other tissues, such as the breast. Tamoxifen is used to prevent breast cancer in women who are at high risk for the disease. However, using tamoxifen for more than 2 years increases the risk of endometrial cancer. This risk is greater in postmenopausal women.
Raloxifene is a SERM that is used to prevent bone weakness in postmenopausal women. It does not have estrogen-like effects on the uterus and has not been shown to increase the risk of endometrial cancer. Other SERMs are being studied in clinical trials.
Hereditary nonpolyposis colon cancer syndrome
Hereditary nonpolyposis colon cancer (HNPCC) syndrome (also known as Lynch Syndrome) is an inherited disorder caused by changes in certain genes. Women who have HNPCC syndrome have a much higher risk of developing endometrial cancer than women who do not have HNPCC syndrome.
Other inherited conditions
Obesity increases the risk of endometrial cancer. This may be because obesity is related to other risk factors such as estrogen levels, polycystic ovary syndrome, lack of physical activity, and a diet that is high in saturated fats.
It is not known if losing weight decreases the risk of endometrial cancer.
The following protective factors may decrease the risk of endometrial cancer:
Combination oral contraceptives
Taking contraceptives that combine estrogen and progestin (combination oral contraceptives) decreases the risk of endometrial cancer. The protective effect of combination oral contraceptives increases with the length of time they are used, and can last for many years after oral contraceptive use has been stopped.
While taking oral contraceptives, women have a higher risk of blood clots, stroke, and heart attack, especially women who smoke and are older than 35 years.
Physical activity may lower the risk of endometrial cancer.
Pregnancy and breast-feeding
Estrogen levels are lower during pregnancy and when breast-feeding. Being pregnant and/or breast-feeding may lower the risk of endometrial cancer. The risk of endometrial cancer may be lower in women who have a higher number of pregnancies and who breast-feed for more than 18 months.
A diet low in saturated fats and high in fruits and vegetables may lower the risk of endometrial cancer. The risk may also be lowered when soy-based foods are a regular part of the diet.
Cancer prevention clinical trials are used to study ways to prevent cancer.
Cancer prevention clinical trials are used to study ways to lower the risk of developing certain types of cancer. Some cancer prevention trials are conducted with healthy people who have not had cancer but who have an increased risk for cancer. Other prevention trials are conducted with people who have had cancer and are trying to prevent another cancer of the same type or to lower their chance of developing a new type of cancer. Other trials are done with healthy volunteers who are not known to have any risk factors for cancer.
The purpose of some cancer prevention clinical trials is to find out whether actions people take can prevent cancer. These may include eating fruits and vegetables, exercising, quitting smoking, or taking certain medicines, vitamins, minerals, or food supplements.
New ways to prevent endometrial cancer are being studied in clinical trials.
Clinical trials are taking place in many parts of the country. Information about clinical trials can be found in the Clinical Trials section of the NCI Web site. Check NCI's list of cancer clinical trials for endometrial cancer prevention trials that are now accepting patients.